Epidermal growth factor (EGF) levels are significantly lower in infants with severe bronchopulmonary dysplasia (BPD) compared to levels in infants who do well. Studies suggest that cortisol sufficiency and nutrition may control early EGF concentrations. We will match cortisol levels with EGF levels, nutrition parameters and pulmonary acuity in preterm infants. A blinded, placebo-controlled study of severe BPD will explore the effects of glucocorticoid on pulmonary weaning, EGF levels and recovery of adrenal axis.